1. Field of the Invention
The present invention relates to a liquid-jet head and a liquid-jet apparatus, and particularly relates to an ink-jet recording head and an ink-jet recording apparatus where a part of a pressure generating chamber communicating with a nozzle orifice for ejecting ink droplets is formed of a vibration plate, and droplets are ejected by driving an actuator device provided with the vibration plate.
2. Description of the Related Art
There has been an ink-jet recording head where a part of a pressure generating chamber communicating with a nozzle orifice for ejecting ink droplets is formed of a vibration plate ink, and where pressure is applied onto ink in a pressure generating chamber by driving an actuator device provided with the vibration plate, and whereby ink droplets are ejected through the nozzle orifice. In a case of using a piezoelectric element for an actuator device, each of the following two types has been in practical use. One type uses a piezoelectric actuator which operates in a lateral vibration mode whereby the piezoelectric actuator is elongated and contracted in an axial direction of piezoelectric elements. The other type uses a piezoelectric actuator which operates in a flexure-vibration mode. Additionally, as the one using a piezoelectric actuator which operates in the flexure-vibration mode, for example, there has been known one where a piezoelectric element is formed in a manner that a uniform piezoelectric material layer is formed all over the surface of a vibration plate thereof by using a deposition technique, and that, by use of a lithography method, this piezoelectric material layer is divided into parts each being in a shape corresponding to one pressure generating chamber in order that the respective parts can be independent from one another so as to correspond to the respective pressure generating chambers.
Additionally, there has been proposed a liquid-jet head where a protective plate provided with a driver IC is joined to the surface of a side of a passage-forming substrate, the side having piezoelectric elements, and where the driver IC on the protective plate and piezoelectric elements are electrically connected through wiring (for example, see Japanese Patent Laid-open Official Gazette No. 2004-34293, Pages 7 to 9, FIGS. 1 to 3). In this liquid-jet head, pads are provided to the driver IC and are electrically connected through bonding wires to the wiring lines drawn out from the respective piezoelectric elements.
However, because an external wiring line formed of a flexible print circuit (FPC) is connected to the protective plate, there has been a problem that, while wiring for connecting the external wiring and the driver IC is required on the protective plate, thus resulting in an cost increase, and that routing for the wiring is required, thus resulting in upsizing the head and a cost increase. In addition, there has been a problem that, if the external wiring is connected to the protective plate, a region for connecting the external wiring is required, and thus upsizing the head.
Additionally, there has been proposed one where, by previously connecting an external wiring line with a driver circuit, and by fixing the driver circuit on a joint plate provided to a side of a passage-forming substrate, the side having piezoelectric elements, lead electrodes drawn out from individual electrodes of the respective piezoelectric elements and the driver circuit are electrically connected to each other through bonding wires (for example, see Japanese Patent Laid-open Official Gazette No. 2003-63000, Page 5, FIGS. 1 and 2).
However, Japanese Patent Laid-open Official Gazette No. 2003-63000 provides the one which is obtained by previously mounting the driver circuit on the wiring line, and fixing the driver circuit on the joint plate, and which is nothing more than one where the driver circuit and the lead wiring line drawn out from the individual electrodes of the respective piezoelectric elements are electrically connected to each other through bonding wires. In Japanese Patent Laid-open Official Gazette No. 2003-63000, there is no mention on a common electrode common to a plurality of piezoelectric elements. Specifically, in general, because a relatively high voltage is applied to a common electrode common to a plurality of piezoelectric elements, electrical connection to the common electrode through a driver circuit from external wiring has not been practiced.